As the world’s eyes turn to Beijing for the 2022 Winter Olympics, residents and athletes will be breathing easier with air pollution significantly reduced since the last Olympics hosted by the city in 2008, according to a new analysis by the Air Quality Life Index (AQLI). Pollution countrywide has declined by about 40 percent, and by about 50 percent in Beijing thanks to the country’s “war against pollution” since 2013. In most areas of China, pollution has fallen to levels not seen in more than two decades. Because of these reductions in pollution, the average Chinese citizen can expect to live 2 years longer and residents of Beijing can expect to live about 4 years longer, if the reductions are sustained.

“The air people in Beijing breathe today is dramatically cleaner than it was during the last Olympics, allowing residents to live longer, healthier lives,” says Michael Greenstone, the Milton Friedman Distinguished Service Professor in Economics and creator of the AQLI along with colleagues at the Energy Policy Institute at the University of Chicago (EPIC). “The speed of these reductions is without historical precedent globally. At the same time, there are opportunities to further increase lifespans through additional reductions in air pollution.”

To put China’s success into context, the reductions in pollution account for more than three quarters of the global decline since 2013. It took several decades and recessions for the United States to achieve the same pollution reductions that China has accomplished in seven years. But while China has met its national air quality standard, its pollution levels still exceed World Health Organization guidelines. When compared to the most polluted city in the United States, Los Angeles, Beijing is still three times more polluted. If China were to meet the WHO guideline, the average Chinese citizen could expect to gain an additional 2 years of life expectancy, on top of the recent gains. Residents of Beijing could gain an additional 3 years.

“As China enters the next phase of its war against pollution, leaders may find it difficult to continue this swift decline in pollution as it’s possible the country has already captured the low-hanging fruit and done so at a high cost for its residents,” says Ken Lee, the director of the AQLI. “This points to an opportunity to change tactics from the tough, command-and-control policies that have worked over the last several years to lower-cost approaches that better align incentives, market structures and local realities.”

Prior to the 2008 Olympic Games, China took swift, targeted actions to reduce pollution such as temporarily suspending production at many power plants. But the actions managed to only slow the climb in pollution. It wasn’t until the country began enforcing sustained, command-and-control-style rules that pollution levels made a sharp downturn. These approaches—like closing polluting plants, enforcing tighter emissions standards and assigning binding abatement targets to local governments—also came with high costs. For example, at one point, the government left many households without heat during winter after removing coal boilers before natural gas or electric replacements could be installed.

“Leaders have the opportunity to make their progress more durable moving forward through lower-cost, market-based approaches,” says Guojun He, research director at EPIC-China and a professor at the University of Hong Kong. “With the carbon market now implemented, extending such a market to other forms of emissions would make sense and be easy to accomplish. Such approaches have been successful in reducing pollution at a low cost in other parts of the world.”